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peter urhegyi
Joined: 26 Oct 2020 Posts: 28
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Posted: Sun Apr 16, 2023 9:47 pm Post subject: 16-04-2023 VH |
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A sudoku as I like to see more in the daily sudokus. Only X,XY,XYZ wings, but this time a lot of them:
Code: |
+-------+-------+-------+
| 6 . . | . . 2 | . . . |
| . 2 . | . . . | . 5 . |
| . . 3 | . 5 . | 8 . . |
+-------+-------+-------+
| . . . | . . 5 | . . 7 |
| 2 . . | . 8 3 | 4 . . |
| . . 8 | 1 7 . | . . . |
+-------+-------+-------+
| . . . | . . . | 7 . . |
| . 9 . | 6 . . | . . 2 |
| . . 1 | . . . | . 3 6 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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dongrave
Joined: 06 Mar 2014 Posts: 565
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Posted: Tue Apr 18, 2023 4:31 pm Post subject: |
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Thanks for the puzzle Peter! After basics:
Code: | +----------------+---------------+---------------+
| 6 1458 459 | 348 19 2 | 39 7 1349 |
| 14789 2 479 | 3478 19 78 | 6 5 1349 |
| 1479 bf14 3 | e47 5 6 | 8 2 g149 |
+----------------+---------------+---------------+
| 149 b134 49 | 2 6 5 | a39 8 7 |
| 2 7 6 | 9 8 3 | 4 1 5 |
| 59 35 8 | 1 7 4 | 2 6 3-9 |
+----------------+---------------+---------------+
| 3 6 2 | 5 4 1 | 7 9 8 |
| 578 9 57 | 6 3 78 | 1 4 2 |
| 478 c48 1 | d78 2 9 | 5 3 6 |
+----------------+---------------+---------------+ |
I solved it using the following 6 VH moves but I'm not sure if they were all necessary. (I'll go back and check.) Note that you can apply the first 3 steps in any order.
Step 1. X Wing on 7's in rows 3 and 9 (-7r2c14,-7r8c1).
Step 2. X Wing on 9's in rows 3 and 6 (-9r1c9,-9r2c19,-9r4c1).
Step 3. XY Wing 78-4 at r3c4,r9c24 (-4r3c2).
Step 4. XY Wing 78-4 at r2c16,r3c4 (-4r2c4,-4r3c1).
Step 5. XYZ Wing 479 at r24c3,r3c1 (-9r1c3).
Step 6. XY Wing 48-5 at r1c3,r28c1 (-5r8c3).
Then I went back and solved it in one step by using the following chain: (9=3)r4c7-(3=1|4)r34c2-(4=8)r9c2-(8=7)r9c4-(7=4)r3c4-(4=1)r3c2-(14=9)r3c9 => r6c9 <> 9; stte. |
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dongrave
Joined: 06 Mar 2014 Posts: 565
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Posted: Fri Apr 21, 2023 9:20 pm Post subject: |
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I hope that I'm not dissuading others from posting their solutions to the VH/VH+ puzzles on this 'Other puzzle' link. If anyone out there does not like me posting solutions so quickly, just let me know! I'd be glad to try to solve them but refrain from posting a solution (if I'm lucky enough to find one). |
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TomC
Joined: 30 Oct 2020 Posts: 352 Location: Wales
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Posted: Sat Apr 22, 2023 10:49 am Post subject: |
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Nice puzzle Peter!
First time I did this I used lots of steps like dongrave (maybe more), I did use a <14> W wing in there as well
But on seeing dongrave's solution lead me to another one stepper below
Code: |
+------------------+----------------+---------------+
| 6 d1458 459 | 348 19 2 | 39 7 1349 |
| 14789 2 479 | 3478 19 a78 | 6 5 1349 |
| 1479 14 3 | 47 5 6 | 8 2 149 |
+------------------+----------------+---------------+
| 149 134 49 | 2 6 5 | 39 8 7 |
| 2 7 6 | 9 8 3 | 4 1 5 |
| 59 35 8 | 1 7 4 | 2 6 39 |
+------------------+----------------+---------------+
| 3 6 2 | 5 4 1 | 7 9 8 |
| 578 9 c57 | 6 3 b78 | 1 4 2 |
| 478 48 1 | 78 2 9 | 5 3 6 |
+------------------+----------------+---------------+
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Remove <8> from r2c6 to solve
If a=8, b=7, c=5, d=5 leads to no <8> in row 1
It's always nice to see different ways of solving, carry on dongrave! |
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glesco
Joined: 12 May 2022 Posts: 36
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Posted: Sat Apr 22, 2023 9:06 pm Post subject: |
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Using my pen & pencil method, starting approximately where dongrave has the puzzle, I used the "3D Medusa" method. Starting with a base on Row 6, I eventually found a contradiction with 4s on column 2. That solved a lot with basic techniques to complete. |
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immpy
Joined: 06 May 2017 Posts: 570
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Posted: Tue Apr 25, 2023 5:55 pm Post subject: |
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Great puzzle showcasing the VH solving techniques. Thanks peter. |
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